BJA
Correspondence
and should be investigating this in the laboratory before imposing synthetic colloid therapy protocols on patients.
Declaration of interest
None declared.
T. E. Woodcock*
T. M. Woodcock
Southampton, UK
*
E-mail: [email protected]
of the ODM data (the normal theatre situation) had been responsible for their fluid management.
It appears that the same fluid maintenance rate (10 ml
kg21 h21 Hartmann’s solution) was recommended in
patients undergoing laparoscopic and open surgery. It
would be interesting to know whether the extra volume of
colloids administered to the GDT patients within these
groups differed, and also whether there was any outcome
difference when comparing laparoscopic with open surgery.
Declaration of interest
1 Woodcock TE, Woodcock TM. Revised Starling equation and the
glycocalyx model of transvascular fluid exchange: an improved
paradigm for prescribing intravenous fluid therapy. Br J Anaesth
2012; 108: 384– 94
doi:10.1093/bja/aes151
Intraoperative goal-directed fluid therapy
in aerobically fit and unfit patients having
major colorectal surgery
None declared.
J. Rivers*
Bath, UK
*
E-mail: [email protected]
1 Challand C, Struthers R, Sneyd JR, et al. Randomized controlled trial
of intraoperative goal-directed fluid therapy in aerobically fit and
unfit patients having major colorectal surgery. Br J Anaesth
2012; 108: 53–62
doi:10.1093/bja/aes152
Letter 1
Editor—I read with interest the article on using the oesophageal Doppler monitor (ODM) for goal-directed fluid therapy
during surgery for patients undergoing major colorectal resection.1 The study clearly adds important new information
to the knowledge base in this area and raises concern that
using fluid boluses to maximise stroke volume during this
surgery in fit patients may lead to adverse effects. As a
trainee, I have worked with various anaesthetists who have
used ODM and other less invasive cardiac output monitors
to guide fluid management during surgery. In some situations, particularly during open surgery, using the information
from the ODM has led to an increase in fluid administered,
while in others, particularly in laparoscopic surgery, the opposite has been true. Thus, in some cases, cardiac output monitoring has ‘directed’ increased fluid administration, and in
others, it has ‘directed’ fluid restriction. From the design of
your study, it appears inevitable that the goal-directed
group would receive more fluid than the control group. The
ODM data were only available to the investigator, who could,
according to the algorithm, give boluses of colloids, until no
further increase in stroke volume was recorded. At this
point, they would give no further fluid. The anaesthetist
without this information would continue to give maintenance
and other fluid they felt necessary. The ODM algorithm did not
allow the investigator to do anything except give extra fluid,
and the investigator was not able to stop further fluid being
given by the anaesthetist where it was not indicated in the algorithm. It was therefore inevitable that the goal-directed
fluid therapy (GDT) group received more fluid than control.
The study design appears to lead to more fluid being given
than might have been if the ODM data were visible to the anaesthetist. A subgroup of patients may thus have had more
fluid given than they would if a single person in possession
1036
Letter 2
Editor—This study1 provides a surprising result demonstrating a decreased time to fitness for discharge in patients
with an anaerobic threshold (AT) of .11 ml O2 kg21 min21
who received goal-directed fluid therapy (GDT) compared
with those who did not. This is in contrast to the large
body of available data supporting the use of GDT in open
surgery and the NICE technology appraisal. In view of this
striking difference, we need to consider factors contributing
to this result. It is interesting to note that the GDT group
had almost three times the rate of admission to critical
care in a relatively small total patient number; does this
reflect a cause in delay for discharge or consequence of excessive fluids? It is hard to see from the data presented
exactly what led to the delayed readiness for discharge as
tolerance of diet, bowel movement, flatus passed, renal complications, and postoperative complications did not show any
significant difference between the two groups. It is interesting
that the authors made no distinction between the use of
ODM-guided GDT in the laparoscopic and open groups. The
studies demonstrating the benefit of ODM GDT derive from
studies focusing primarily on open surgery. Indeed, it is hard
to find a trial demonstrating a proven benefit of using ODMguided fluids in patients undergoing laparoscopic colorectal
resection. It is possible to find studies using the ODM to demonstrate changes in cardiac index and systemic vascular resistance as a result of the Trendelenburg position and
pneumoperitoneum associated with laparoscopic colorectal
surgery.2 Could the variability of these factors during a procedure have their own effects on stroke volume (SV) making the
following Deltex ODM SV-based algorithm difficult? Could it
be the case that the extrapolation of this technique to laparoscopic procedures without it being directly proven in this group